Unit 9 - Techniques of Analysis of Flavors Flashcards
T or F: The lay and scientific literature typically claims that humans can discriminate 10,000 odors, but this number has never been empirically validated
T
Humans can discriminate at least ___________ olfactory stimuli
1 trillion
We determined the resolution of the human sense of smell by testing the capacity of humans to discriminate __________________
odor mixtures with varying numbers of shared components
What is the challenge we face with flavor analysis?
Flavors represent 0.1% or less of the food components and since they are present un such small amounts we really do not want to destroy them
Flavor is an integrated response composed primarily of the sensations of ________ and _______
aroma and taste
A key step towards understanding what constitutes the flavor of any foodstuff is to _________________________________ which act, either independently or in combination, to produce a highly characteristic aroma response for that particular product.
establish the chemical nature of those volatile constituents
Relative concentrations of the different flavor impact compounds =
flavor profile
In order to study the chemical basis of a flavor, it is necessary first to ________________________ from the nonvolatile bulk of the food and then by the judicious use of appropriate techniques of physical and chemical analysis to obtain the maximum of qualitative and quantitative information on all compounds of possible sensory importance
isolate the volatile aroma constituents
Name the 3 principal steps in flavour analysis:
1) Isolation
2) Separation
3) Identification (chemical structure)
It must be stressed, in regard to identification procedures, that the most powerful and widely used methods available for characterizing flavor volatiles are mainly instrumental, in particular mass spectrometry linked to _____________________
gas chromatography
What is the main interference in the food flavor analysis industry:
water
T or F: Flavor analysis is considered a complex task
T
The total aroma volatiles normally constitute only a very ______ proportion of the weight of the food, ranging from a few hundred ppm for some strongly flavored fruits to less than 10 ppm for some vegetables
minor
To obtain a sample for study, the chemist must remove the volatile components from the food, free them from large amounts of interfering non-odorous volatiles such as ______ and finally ________ them to a form suitable for analysis
water
concentrate
T or F: the correct choice of isolation and concentration procedures is crucial. The methods chosen must not only be efficient enough to yield an adequate amount of sample for analysis, buy must also give an isolate of high sensory quality. In example, on re-dilution the aroma should closely resemble that of the foodstuff from which it was obtained
T
Food aroma isolates are extremely ______________ frequently containing several hundred individual components. While the volatiles of certain products may be dominated by one class of compound, such as ______ in fruits and __________ in blue cheeses , the range of functional moieties which may be represented in food volatiles is very large indeed
complex mixtures
esters
methyl ketones
T or F: The flavor chemist is of course interested primarily in those food volatiles which exhibit important sensory properties, especially those which function as either character impact or contributory flavor compounds
T
T or F: sometimes the concentration of flavor compounds is too low for instruments to detect them
T
Striking aspect of food aroma is the tremendous range of olfactory ________________ exhibited by simple food odorants
detection thresholds
T or F: Trace constituents in an aroma complex are sometimes of far greater sensory importance than other volatile compounds present in vastly larger amounts.
T
The extreme sensitivity of the ________ in the detection of certain powerful odorants may exceed by several orders of magnitude that of even the most sensitive instrumental detectors available
human nose
The task of analyzing a food aroma isolate is then primarily one of ___________ complicated mixtures of organic compounds into their individual components and determining the _____________ of these components
separating
chemical strucure
Very few odorants have molecular weights in excess of _____
250
Foods consist of a complex matrix comprising _______, _______, _______ and water, the relative amounts of which may vary widely for different products. The major portion of the odorous fraction, which is composed of a range of compounds of widely different _________, ________, and _________ will be distributed in a highly specific manner throughout the bulk of the food
carbohydrates
lipids
proteins
- solubilities
- polarities
- volatilities